(1) Field of the Invention
The invention relates to a partion wall construction having an improvement therein comprising a device for prevention of squeaking at stud and runner engagement when said partition wall is subjected to racking forces.
(2) Description of the Prior Art
In high rise construction, significant wind loading can cause many design problems. When wind speeds reach and exceed about 35 mph (56 kph) wind deflection occurs. The horizontal wind sheers tend to move a floor horizontally past the floor below. With the wide use of partition wall construction utilizing metal studs and metal channels, a phenomenon occurs due to such wind deflection. When the building is sustaining these increased wind loads, a partition wall may emit squeaks, creaks or clicking noises. The phenomenon appears most prevalent in the middle third of such high rise buildings and particularly in those walls parallel to the wind direction. This problem has manifested itself in both steel and reinforced concrete frame structures. It has been learned that the source of the noise is at the stud and runner intersections. The sound emitted tends to be cyclic in nature following in response to racking forces imparted to the partition by building drift and twist under moderate to high wind velocities.
If a building sways with a single bend, i.e. less than one mode, the accumulated floor-to-floor horizontal displacement accounts for the total drift at the top of the building. A drift of one foot (0.3 m) at the top of a 100 story building would result in an average 1/8" (0.3 mm) floor-to-floor horizontal displacement. The calculated drift of a high rise structure is based on wind velocity supplied by local building codes and may be grossly underestimated based upon wind tunnel research. The magnitude of true racking, i.e. translation of a rectangular building bent into a parallelogram, is not directly related to horizontal floor-to-floor displacement. Some of the displacement is accounted for by bent rotation as a result of column elongation and compression. Additionally, it is not at all unnatural for a tall slender building to have several bending modes and nodal points, thereby reducing the total drift in one direction. However, there may yet be sufficient racking between floor and ceiling runners to cause rotation or sliding of the studs within the runners. The problem of creep in flat slab construction can also contribute to the squeak problem. Deflection of the ceiling slab forces the top ends of the center studs to seat into the ceiling runner and the bottom ends of the end studs to seat into the bottom runner. This tends to inhibit partition rotation within the frame inducing more of a sliding motion between the studs and runners during building deformation. Attachment of conventional wall board to studs prevents stud rotations within the partition further inhibiting rotation and encouraging sliding. The net result is the strong potential for scraping between the ends of the studs and the web of upper and lower runners.
Until two to three decades ago, most large high rise structures were constructed so massively, using masonry walls, that wind pressure was seldom critical. That design has changed drastically within the last fifteen years and new techniques of construction for tall slender buildings utilize non-structural curtain walls. Also, the wide use of partition wall construction utilizing spaced-apart rows of wall board, which are non-load bearing, has resulted in the recited phenomenon. With the ever increasing cost of building construction, it is unlikely that the new building techniques for the structural portion of buildings will be altered and thus the solution to the problem lies in the design of partition walls for use in such constructions.
(3) Objects of the Invention
It is accordingly a primary goal of the invention to solve the problem of squeaking and clicking emitted from partition wall construction as experienced in high rise construction.
It is a further goal of the invention to solve the problem in an economic manner without drastic alteration of partition wall elements and with minimal added cost.
It is also an important goal of the invention to provide an improved partition wall construction which may be successfully subjected to thousands of racking cycles as would be normally experienced for a high rise building during its life-time.